Applicants reference herein the patent applications of BOUDIAF BOUSSOUIRA and DIDIER CANDAU for COMPOSITION COMPRISING A DIBENZOYLMETHANE DERIVATIVE AND A POLYAMINO POLYMER (Docket No. 05725.0304), and of BOUDIAF BOUSSOUIRA and CHRISTIAN COLIN for COSMETIC USE OF SELECTED POLYAMINO POLYMERS AS ANTIOXIDANTS (Docket No. 05257.0306), filed on even date herewith and incorporate the disclosures thereof specifically by reference herein.
The present invention relates to novel cosmetic and/or dermatological compositions (hereinafter known as anti-sun compositions) intended for the protection of the skin and/or hair against UV radiation, in particular solar radiation. More specifically, it relates to novel cosmetic and/or dermatological compositions exhibiting an improved photostability and comprising, in a cosmetically and/or dermatologically acceptable vehicle, the combination of two specific compounds.
The invention also relates to the use of these compositions in the cosmetic and/or dermatological fields.
It is known that light radiation with wavelengths ranging from 280 nm to 400 nm makes it possible for the human skin to brown and that radiation with wavelengths more particularly from 280 to 320 nm, known under the name of UV-B, cause erythemas and skin burns which can harm the development of natural tanning. For these reasons and for aesthetic reasons, there exists a continual demand for means for controlling this natural tanning, for the purpose of thus controlling the colour of the skin; it is thus advisable to screen out this UV-B radiation.
It is also known that UV-A radiation, with wavelengths ranging from 320 to 400 nm, which causes the skin to brown, are capable of leading to a detrimental change in the latter, in particular in the case of sensitive skin or skin which is continually exposed to solar radiation. In particular, UV-A radiation causes a loss of skin elasticity and the appearance of wrinkles, leading to premature skin ageing. It promotes the triggering of the erythemal reaction or accentuates this reaction in certain subjects and can even be the cause of phototoxic or photoallergic reactions. Thus, for aesthetic and cosmetic reasons, such as preservation of the natural elasticity of the skin, for example, more and more people wish to control the effect of UV-A radiation on their skin. It is thus desirable to screen out the UV-A radiation as well.
Thus, with the aim of providing protection of the skin and hair against all UV-A radiation which is as complete and as efficient as possible, use is generally made, in the manufacture of anti-sun compositions, of combinations of screening agents active in the UV-A and of screening agents active in the UV-B.
In this respect, a particularly advantageous family of UV-B screening agents is currently composed of cinnamic acid derivatives, and in particular 2-ethylhexyl p-methoxycinnamate, because these compounds exhibit a high intrinsic absorption power. In addition, other cinnamic acid derivatives have highly advantageous properties in cosmetics, such as, for example, caffeic acid, which is well known as a depigmenting agent.
Now, some cinnamic acid derivatives exhibit the disadvantage of chemically degrading under certain conditions, in particular when they are exposed to UV radiation. When they are subjected to such degradation, these active principles, derived from cinnamic acid, lose their potential for activity.
Use is frequently made, in anti-UV compositions, of tocopherol derivatives, which are known for their properties in combating free radicals and which contribute, via these properties, to retaining the youthfulness of the skin.
However, the inventors have found that cinnamic acid derivatives, in particular 2-ethylhexyl p-methoxycinnamate, when they are in the presence of tocopherol derivatives and under UV irradiation, chemically degrade to a significant extent. Under these conditions, the combination of the two compounds no longer allows prolonged broad anti-sun protection of the skin and hair.
Such a degradation reaction is particularly significant when the cinnamic acid derivative is used in combination with another organic screening agent, in particular screening agents of the dibenzoylmethane family, which are anti-UV-A screening agents. In particular, the combination of cinnamic acid derivatives with 4-tert-butyl-4xe2x80x2- methoxydibenzoylmethane is highly advantageous. These screening agents are very often used in combination in skin and hair products because their spectra of activity are complementary.
Now, following significant research carried out in the field of the photoprotection mentioned above, the inventors have now discovered that the introduction of certain polyamino polymers, which will be defined more specifically hereinbelow, into a composition containing a cinnamic acid derivative, in particular 2-ethylhexyl p-methoxycinnamate, made it possible to improve, in an entirely remarkable way, the photostability of this compound within such compositions and thus the overall efficiency of these compositions.
A subject-matter of the present invention is thus novel cosmetic and/or dermatological compositions comprising, in a cosmetically and/or dermatologically acceptable vehicle:
a) at least one cinnamic acid derivative corresponding to the following formula (I): 
in which:
A represents:
an OR3 radical, R3 being selected from: a hydrogen atom, a phytyl or benzyl radical, a saturated or unsaturated, linear, branched or cyclic, C1-C18 alkyl chain, an alkali or alkaline earth metal ion or an ammonium ion, or
an NHR4 radical, R4 being selected from: a hydrogen atom, a phytyl or benzyl radical or a saturated or unsaturated, linear, branched or cyclic, C1-C18 alkyl chain;
R1 represents a radical selected from: H, OH, C1-C6 alkoxy, preferably methoxy, or a saturated or unsaturated, linear, branched or cyclic, C1-C18 alkyl chain;
R2 represents a radical selected from: H, OH or C1-C6 alkoxy, preferably methoxy, and
b) at least one polyamino polymer selected from the following families:
(A) a polyalkylene polyamine selected from:
(i) polyalkylene polyamines;
(ii) alkylated derivatives of polyalkylene polyamines;
(iii) addition products of alkylcarboxylic acids with polyalkylene polyamines;
(iv) addition products of ketones and aldehydes with polyalkylene polyamines;
(v) addition products of isocyanates and isothiocyanates with polyalkylene polyamines;
(vi) addition products of alkylene oxide and poly(alkylene oxide) block polymers with polyalkylene polyamines;
(vii) quaternized derivatives of polyalkylene polyamines;
(viii) addition products of a silicone with polyalkylene polyamines;
(ix) copolymers of dicarboxylic acid and polyalkylene polyamines;
(B) polyvinylimidazoles;
(C) polyvinylpyridines;
(D) addition products of 1-vinylimidazole monomers of formula (1): 
in which the R radical independently represents H or a saturated or unsaturated, linear or cyclic, C1-C6 alkyl radical;
n is an integer ranging from 1 to 3, with the polyalkylene polyamines (A)(i) to (A)(ix);
(E) polymers based on amino acids containing a basic side chain;
(F) crosslinked derivatives of the polymers (A)(i) to (A)(ix), (B), (C), (D) and (E).
Another subject-matter of the invention is novel cosmetic and/or dermatological compositions comprising, in a cosmetically and/or dermatologically acceptable vehicle:
a) at least one cinnamic acid derivative corresponding to the formula (I) defined hereinabove;
b) at least one polyamino polymer as defined hereinabove; and
c) at least one derivative corresponding to the formula (II): 
in which:
Rxe2x80x21, Rxe2x80x22 and Rxe2x80x23 independently represent a radical selected from: H, OH or C1-C6 alkyl, preferably methyl,
Rxe2x80x24 represents a radical selected from: H or C1-C6 alkyl, preferably methyl,
Rxe2x80x25 represents a radical selected from: H or C1-C18 alkyl, among which mention may in particular be made of tocopherol derivatives.
An additional subject-matter of the invention is novel cosmetic and/or dermatological compositions comprising, in a cosmetically and/or dermatologically acceptable vehicle:
a) at least one cinnamic acid derivative corresponding to the formula (I) defined hereinabove,
b) at least one polyamino polymer as defined hereinabove, and
d) at least one dibenzoylmethane derivative corresponding to the following formula (III): 
in which:
R7, R8, R9 and R10 independently represent hydrogen or a hydroxyl radical or a linear or branched C1-C8 alkyl radical or a linear or branched C1-C8 alkoxy radical.